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A kind of method for preparing glycolide by catalytic depolymerization at low temperature and high efficiency

A technology of catalytic depolymerization and glycolide, which is applied in high efficiency, can solve the problems of decreased production of glycolide, increase of by-products, high reaction temperature, etc., and achieve the effect of reducing the temperature of depolymerization and avoiding thermal deterioration.

Active Publication Date: 2016-08-03
CHANGZHOU UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0010] The technical problem to be solved by the present invention is: in the prior art, in the technique of catalytic depolymerization polyglycolic acid (PGA) oligomer, there are problems such as reaction temperature is too high, glycolide output declines, by-product increases

Method used

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  • A kind of method for preparing glycolide by catalytic depolymerization at low temperature and high efficiency
  • A kind of method for preparing glycolide by catalytic depolymerization at low temperature and high efficiency
  • A kind of method for preparing glycolide by catalytic depolymerization at low temperature and high efficiency

Examples

Experimental program
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Effect test

Embodiment 1

[0034] Add 200g glycolic acid oligomer (weight average molecular weight is 12000) in 500ml four-necked flask, and 0.75g catalyst Sb 2 o 3, heated to 240° C., and decompressed to 1 kPa in a nitrogen atmosphere. During the reaction process, a light yellow liquid evaporates until the reaction ends when no light yellow liquid evaporates in the reaction system, and the light yellow solid obtained by cooling is the crude glycolide product. Glycolide yield 84% (yield is calculated by the formula of "m (obtained light yellow solid crude glycolide product) ÷ m (glycolic acid oligomer raw material) * 100% ", the following examples are the same) , the purity is 87.56%, and the coking rate of the reaction system is 13% (the empty reaction bottle is weighed before the reaction, and the coke is weighed together after the reaction, the difference between the two weights is the coking amount, and then the coking amount is divided by glycolic acid The oligomer raw material quality × 100% jus...

Embodiment 2

[0038] Add 200g glycolic acid oligomer (weight average molecular weight: 10000) and 0.75g catalyst ZnO into a 500ml four-neck flask, heat to 240°C, and depressurize to 1kPa in a nitrogen atmosphere. During the reaction process, a light yellow liquid evaporates until the reaction ends when no light yellow liquid evaporates in the reaction system, and the light yellow solid obtained by cooling is the crude glycolide product. The yield of glycolide was 87%, the purity was 85.28%, and the coking rate of the reaction system was 11%.

Embodiment 3

[0044] Add 200g glycolic acid oligomer (weight average molecular weight is 12000) in 500ml four-necked flask, and 0.75g catalyst Zn (acac) 2 , heated to 200° C., and decompressed to 1 kPa in a nitrogen atmosphere. During the reaction process, a light yellow liquid evaporates until the reaction ends when no light yellow liquid evaporates in the reaction system, and the light yellow solid obtained by cooling is the crude glycolide product. The yield of glycolide is 92%, the purity is 99.93%, and the coking rate of the reaction system is 1.5%.

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Abstract

The invention belongs to the field of preparation of glycolide monomers, and particularly relates to a low-temperature high-efficiency preparation process which is beneficial to increase the glycolide yield. The process can obviously reduce the depolymerization temperature of PGA oligomers, increase the glycolide yield and reduce the coking rate of a reaction system. The technical scheme is as follows: under the catalytic action of metal acetoacetonate, polyglycolic acid oligomers, or a mixture of polyglycolic acid and azeotropic solvent, or a mixture of polyglycolic acid, azeotropic solvent and cosolvent is depolymerized to prepare the glycolide monomer; and the reaction temperature of the glycolide monomer preparation based on depolymerization can be reduced to 160-210 DEG C.

Description

technical field [0001] The invention belongs to the field of preparation of glycolide monomers, in particular to a low-temperature, high-efficiency preparation process which is beneficial to improving the yield of glycolide. Background technique [0002] Polyglycolic acid (PGA) is an aliphatic polyester polymer material with the fewest carbon units and can be completely decomposed. It has excellent gas barrier properties, degradability, machinability, heat resistance and biocompatibility , Under the action of human enzymes, it is gradually hydrolyzed, and the hydrolyzed product glycolic acid can be safely absorbed and metabolized by the human body. [0003] At present, high molecular weight PGA is prepared by glycolide ring-opening method: firstly, PGA oligomer is obtained by direct condensation polymerization of glycolic acid, and the oligomer is depolymerized at high temperature to obtain monomer glycolide , The monomer glycolide is refined and purified for many times and...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07D319/12
CPCC07D319/12
Inventor 陈群崔爱军何明阳张鑫姜海建韦梅峻
Owner CHANGZHOU UNIV
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